Distillation of acid-treated oils



Dec. 7, 1948. M. c. KQJONES ETAL DISTILLATION 0F ACID-TREATED OILS Filed Oct. 3, 1946 K-J rzes dw'ard C. Eulhar'a't nvenbcrs Patented Dec. 7, 1948 UNITED sTAtEs Para;

DISmlrEI-ATION; F AQIDLTREFEBGWSH i Minor. K..-Jones,Mountainsl`dc, iandiEdwatd. (L.

Eixllardt; Uiiion,` NL" J., assignors,toastandard.. OVDevelopment.`Company a corporation of" Delaware"-A .eppiicauoni acabar. 3, *1946s serial No.; mossa; l claims (o1. raies-ss).

This invention relates to a process of idistilling. acida't'realted oilsiandlW-ill .be fmllyunderstood from develop certain undesirale. cl'iaracteristicsdue` to. decomposition of compounds containing the acid radical. Since thegreatest advantagesof the. present process are obtained `whenitis-applied' to the redistillation` offacid treatednaph- This. and. other-f objects of` `this .invention ane,.-

accomplishedaby adding: .lesa `tham the .f theoreticai quantity ot talka-ligpreferably :9 0f95.%-,. necessary for. .neutralization of. thea estersfpresent .and'comev nletingtt-he i neutralization bythe i addition of4 suie` fcient. l. amount. Lotta? reactivity promoting mate.-v rial. capable: ofY neutralizing ther .residual acido. Suitable` promoters..` incltldel.-` naphthenicJ acid; soanst. .suchstast sodium f naphthenate. amines,n alkali phenates-,.-.tetrafalkyl ammonium` hydroifr-f-` idee, tetra-alkynol ammonium :hydroxides-,asuch as, tetra1 ethanol ammonium. `hy.droxide and. oil..

thas, and especially of acid treated cracked naphthas, the same" will be `described inmoredetail in conjunctionu with its last'fmentionedapplication.

Redistillation of a cracked naphtha which` has been treated with sulfuric aci'df islrthe `usual method employedfior` improving the .color and' lowering the'gum andl sulfur contenttofs thelstock,

these changes heine"l eii'ectedfthrough remonaly off polymers. Inl `the course:.oiiltiiis` disti'l1`ation;,su1` iur dioxide is. often` evolved Lthroughithe thermal breakdown .otlsulfurinr'acidi esters` present; `in` the acid treated?.charge:A This' gasipa'sses `out of' the still.` in. company Witlr the overhead products,` 1resultioig.'A in serious corrosionA of both overhead equipment.- and vfunnace tubesia-ndl Iheaters. De-

posits inr the tubes intthetreboiier section from. this decomposition:of.` sulfuric. acid: esters reducelieat transfer coeiiicient-si causing rapid rise in the tube metal temperatures and forcing shutdowns for cleaning after runs of short duration.

The addition offCaustioj. soda with solutizers or 1 without: causing corrosiomandoinfoulingzot tsaid i equipment.

soluble soaps, -such ast-.cornoiltsoanIn cocoanut oila soapnotton `seed:.oil,soap..etc. lltfis also .advane tageousftouse. a .smalltamounttot a` hearty oil. suchwas` :iM-clean `fueltoil:alongswith. .the` causticr and:` promoter to; act.. .as a.-v.ehicle s to. .car-ry. along. ann-sediment formation. through' the heater. secr tion. oftthastill..

Referring now tok the` 'figura the.appanat11s-.wil1. be briefly, `described.` in.. conjunction the. methodtof. operatingsthesame.

The. acidtreatedoiltfrorn. tank.` l. and the. caus-` tia. containing. the.` promoter. from. tank 2 are passedby. meansof pumps-.Landathroughimeters. 5. andi Gandlinal. intmthere-run battery.` About, 05.%. of...a..heavytoil" mayhaadded if; desired.. Ther.re nun...hattery,. in. case. of.. redistilling; nanhf tha.. .mayV consist. et. tower .8 which. is` heated.'oy.` meansoftaclosed steamcoil..9. at the;` bottom.. thereof.; The tower.. is. l.prortidad; with. `the usual. bell cap plates. All of the unvaporized.residuaist` removed-through .line1 .Ll ,intoresidue tant:` `l-2. Overhead... distillate. which.. leaves the; tower4 through line l.....is..condensedin condenser: UL whicnis connectediwith atsource. oLi/.acumrrby line` I5. The...condensei1. distillate, is.. passedl thnough. line t6 .b. f. pumpglfli to` the distillate` tank` [8o. The.. line`` i9 serves ior f the return vof redux. condensatef to .the tower..

" `Below i are.. tabulatedwthreez lruns. showing.; the` effect. oi` usingzmorefthan..theoretical caustic` re` quirements inthe. frst-.case,..and..the stoichio. met-ric.. amount .with a .cox-itactpromoter. inthe. second; .and the... above., recommended procedure of :..adding,- of. .the stoichiometric amount..` ot causticsodaplus Contact promoter inthe` form` ci sodium naphtl'ienates. .from caustic@ washing, naplzitnenic` acids. from. a.. suitable heating oil',

. fractionin, the thirdcasadn testina acid treated.

catalytic naphtha in a laboratory type, heater fouling test. and...id1sti11ation..equipment; Such labora-twig;` eguipment. reprcuiilces.A the` response.

of full scale plant equipment to similar conditions.

what is claimed as new and useful and is desired to be secured by Letters Patent is:

l Exactly to neutralize the estcr content found by quantitative analysis.

The rst run, in which an excess amount of caustic soda only was added, shows a rather high sediment formation in the heater fouling test and only a 63% reduction in sulfur dioxide formation in the distillation test. In the second case Where exactly the theoretical quantity of caustic plus the contact promoter was used, the effect of the solutizer was seen in the greater reduction of sulfur dioxide formation. However, sediment formation he-re was much higher than with caustic soda alone, but some advantage was gained inthat the deposit Wa'svsoft and muddy in appearance and in production furnace and heat exchanger tubes does not build up to a great extent. The third run, where caustic soda and sodium naphthenate were added in the amounts found to be critical, produced the best results. Here sediment formation was less than half than where caustic soda alone was used and 'sulfur dioxide reduction was excellent,

In experimental distillation's made in glass ap paratus, the change in color and appearance of the acid-treated gasoline was evident by visual observation. Acid treated gasolines of appreciable ester content, from `saylO to 50 ester number (milligrams of N/ l acidity formed per 100 ml.), were distilled with and without the addition of sodium hydroxide solution for neutralization and tetraethanol ammonium'hydroxide as a contact or reaction promoter, in the manner described. When thev acid-treated gasolines were distilled, they gradually darkened to a black color (due to decomposition of the esters), with evolution of sulfur dioxide in the overhead. However, when the neutralization and reaction promoter formula and technique was applied, the gasoline in the distillation ilask remained olea-r and of its original color, and only traces of sulfur dioxide were noted. These experiments demonstrated the improvement in deposit formation which is possible in distilling acid-treated petroleum distillates.

By way of illustrative explanation of the mechanism by which the favorable results are attained, it may be postulated that the sulfuric acid esters in the acid treated distillate react to the extent possible with the promoter, say oil soluble sodium naphthenate, releasing oil soluble naphthenic acids. These acids resaponify with the sodium hydroxide present and the reaction is repeated, until all the esters have reacted with (lower cost) sodium hydroxide through the route of the oil soluble promoter. `Carbon deposition is thus avoided andsuliur dioxide evolution does not take place. At the same time, the cementlike action of a mixture of sodium hydroxide, sodium sulfate `and .carbon is avoided, so that hard deposits do not build up in heat exchanger and furnace tubes. However, it is not intended to be bound by any theory of the mechanism of the reaction.

The nature and objects of the present invention having been thus described and illustrated,

1. The process of distilling an acid-treated mineral oil which comprises adding 90-95% of the stoichiometric quantity of caustic alkali necesnecessaryvto neutralize any acid reacting substance evolved from any residue of the treating acid during the distillation of the oil, said caustic alkali solution containing a suiiicient amount of a naphthenic acid soap to be capable of completing said neutralization and carrying out the distillation in the presence of said caustic alkali and naphthenic acid soap. l i

3. The process of distilling an acid-treated mineral oil which comprises adding SiO-95% of the stoichiometric quantity oi sodium hydroxide necessary to neutralize any acid reacting substance` evolved from any residue of the treating acid during the distillation of the oil, together with a sufficient amount of sodium naphthenate capable of completing said neutralization, and carrying out the distillation in the presence of said sodium hydroxide, and sodium naphthenate.

4. The process of distilling an acid treated mineraloil which comprises adding 90-95% of the stoichiometric quantity of sodium hydroxide solution necessary to neutralize any acid reacting substance evolved from any residue of the treatingacid during the distillation of the oil, said sodium hydroxide solution containing a sufficient amount of sodium naphthenate capable of completing said neutralization, and carrying out the distillaticnin the presence of said sodium hydroxide and sodium naphthenate.

MINOR C. K. JONES. EDWARD C. EULHARDT.

REFERENCES CITED The following references are of record in the file of this patent: f 

